In playing games of chance, it is traditional for an individual player or dealer to "throw" two or more dice in order to obtain a score based on the value of the upper faces of the dice when they come to rest. If the game is to be truly a "game of chance", it is required that the dice fall in a random manner, uninfluenced by the thrower's technique in rolling or tossing the dice.
To minimize any effects of the individual's throwing technique, a dice cup may be used instead of bare hands to shake or roll the dice.
U.S. Pat. No. 2,225,519 is directed to a shaker box with a base designed to trap and display the dice as they have randomly fallen.
Another type of dice cup makes use of a transparent wall which forms a chamber to contain the dice upon a flat receiver. The player shakes the dice within the cup, and then sets it upon a table so that the receiver rests upon the table. As the cup is set upon the table, the dice fall upon the receiver and come to rest in a chance-controlled arrangement. The score of the dice may be read through the transparent wall of the chamber. Dice cups with transparent walls are described in U.S. Pat. Nos.: 148,374; 1,781,983; and 3,892,410.
To further minimize the possibility of the thrower influencing the outcome, a cup with a transparent wall may be enclosed within a non-transparent cover prior to the throw. After the cup is resting on the table, the cover is removed without disturbing the arrangement of the dice, and the score is read through the transparent wall.
The dice must be equally weighted on all sides in order to assure that the outcome of the throw is truly random. A dishonest player or dealer might substitute weighted dice in order to predict which sides will face upwards most often, and thus predict the resulting score. Dice might also be made with asymmetrically placed metal inclusions, which would allow an unscrupulous player or dealer to control the fall of the dice through surreptitious use of a magnet.
Because of the potential for substitutions of non-standard dice, gaming establishments such as card rooms prefer to use a dice cup which contains the dice more securely than the above described cups. Currently in use are cups with threaded lower walls which screw on to a threaded receiver. This makes it more difficult for a player or dealer to substitute dice during a game because the manipulations involved in opening the cup would be noticed by the other players. However, before or between games there still exists the potential for surreptitious dice substitutions by anyone with access to the loaded dice cup.
What is needed is a dice cup that can be locked with the dice in place. This would allow the gaming establishment to control access to the interior of the cup and therefore prevent dice substitutions. Moreover, an authorized person with a key could open the cup to inspect the dice and replace them with authorized dice, if needed.